The present invention relates to a robot apparatus, and more particularly to a robot apparatus for installing parts on a workpiece, the robot apparatus including a robot body having an arm to which a wrist mechanism is rotatably attached through a support shaft having a passage for supplying a fluid under pressure, the wrist mechanism being angularly movable by an actuator, and a running mechanism disposed in a pit defined in a floor for displacing the robot body, the robot apparatus being of a relatively simple arrangement capable of automatically installing parts automatically and accurately, and effectively utilizing a relatively small space for installtion.
Heretofore, production systems have widely been employed which include a plurality of working stations disposed along an assembly line for installing various parts on a workpiece such as an automobile body with installing mechanisms such as robots. Each of the working or installing stations has a robot for attaching parts such as passenger seats to an automobile body being conveyed, a jig stocker for storing jigs to be attached to the distal end of the robot for holding parts to be installed on the automobile body, and a workpiece stocker for storing an array of parts such as passenger seats.
Various robots to be disposed in the working stations have been developed in order to hold different types of parts. One such robot is disclosed in Japanese Laid-Open Patent Publication No. 59-97877. The disclosed robot basically includes a base table displaceable in a prescribed direction for attaching a passenger seat, particularly a front seat, to an automobile body, a first swingable arm disposed above the base table, a second arm swingably supported on the distal end of the first arm, and a grip hand mounted on the distal end of the second arm through a rotatable wrist mechanism. The seat is held by the hand, and the first and second arms are actuated to install the seat on the automobile body. The wrist mechanism houses therein a fluid-pressure-operated rotative drive source for turning the wrist mechanism including the hand.
Where the disclosed robot is employed to mount a relatively heavy component such as a rear seat in an automobile body, the first and second arms and the grip hand are caused to flex to a considerable degree due to the weight of the component to be installed and also the weight of the arms and the grip hand. Therefore, the component to be attached may not be held in a desired position, and it is difficult to automatically install the component on the automobile body because the component held by the grip hand suffers a positional deviation or error. To avoid this difficulty, a component has to be positionally aligned each time it is installed.
With the rotative drive source accommodated in the wrist mechanism for turning the hand, there must be provided a pipe for supplying a fluid to the rotative driver source and a directional control valve such as a servovalve disposed in the pipe for turning the wrist mechanism in a desired direction. The procedure of attaching the pipe and the valve is considerably complex. If the number of steps required for attaching the pipe and the valve is increased, an error may be caused in the installation of the pipe and the valve. The pipe and the valve make the robot itself highly complicated, and places a substantial limitation on the movement of the robot.
A running mechanism is also required to displace the robot in a directed direction. Such running mechanisms are disclosed in Japanese Laid-Open Patent Publication No. 58-33579 and Japanese Laid-Open Utiilty Model Publication No. 60-85284. More speciically, the former publication shows a running device for conveying in a prescribed direction a device for automatically mounting a spare tire on an automobile body. The latter publication shows a running mechanism for delivering a device for installing a door on an automobile in order to convey the installing device in a prescribed direction.
The device for automatically mounting a spare tire on an automobile body or the device for installing a door on an automobile is generally disposed on a floor. Therefore, the running device or mechanism itself takes up a large space, and the space around a working station where the mounting or installing device is positioned cannot effectively be utilized.
SUMMARY OF THE INVENTION
It is a general object of the present invention to provide a robot apparatus including a wrist mechanism held by a link mechanism including an actuator and coupled to an arm by a support shaft with a passage defined therein for supplying a fluid to a rotative drive source for actuating the wrist mechanism, and a running mechanism disposed in a pit defined in a floor for moving a robot in a prescribed direction, so that the robot apparatus is simple in structure, can hold and deliver heavy objects or parts without causing a robot hand to suffer a positional deviation or error, can automatically and accurately install various parts, and can effectively utilize a small space for installation.
Another object of the present invention is to provide a robot apparatus including a robot having an attachment member, an arm swingably mounted on the attachment member, a wrist mechanism mounted on the arm, a connecting member interconnecting the attachment member and the wrist mechanism, and a running mechanism for displacing the robot in a prescribed direction, the connecting member including an actuator and a link coupled thereto for displacing the wrist mechanism with the actuator.
Still another object of the present invention is to provide a robot apparatus, wherein the actuator includes a cylinder and the link includes a piston rod of the cylinder.
A further object of the present invention is to provide a robot apparatus, further including an actuator connected to an intermediate portion of the arm and mounted on the robot, and a moving member movable by the actuator for swinging the arm.
A further object of the present invention is to provide a robot apparatus, further including a rotative drive source, a holder rotatable by the rotative drive source, the attachment member being mounted on the holder, and a position detector for detecting an angular position of the holder to stop the holder in a desired position.
A yet further object of the present invention is to provide a robot apparatus, wherein the wrist mechanism includes a bracket coupled to the arm, a rotative drive source disposed in the bracket, a rotatable body rotatable by the rotative drive source, and a support shaft by which the bracket is supported on the arm, the support shaft and the bracket having fluid passages defined therein for supplying fluid under pressure to actuate the rotative drive source.
A still further object of the present invention is to provide a robot apparatus, further including a directional control valve for selecting desired ones of the fluid passages, and means on the bracket for attaching the directional control valve.
A yet still further object of the present invention is to provide a robot apparatus, wherein the attaching means has passages communicating respectively with ports of the directional control valve.
Yet another object of the present invention is to provide a robot apparatus, wherein the directional control valve includes a servovalve.
Yet another object of the present invention is to provide a robot apparatus, wherein the rotative drive source includes a torque actuator operable by fluid under pressure.
Still another object of the present invention is to provide a robot apparatus, wherein the support shaft is fitted in the bracket, the support shaft having a plurality of grooves defined therein, the bracket having a plurality of passages defined therein and communicating with the grooves, the grooves and the passages jointly providing the fluid passages.
A further object of the present invention is to provide a robot apparatus, wherein the grooves are kept hermetically sealed in a fluid-tight manner.
A still further object of the present invention is to provide a robot apparatus, wherein the support shaft is rotatably coupled to the arm.
A still further object of the present invention is to provide a robot apparatus, wherein the running mechanism includes a base table, at least one displaceable running table, driver means for moving the at least one displaceable running table, and an attachment member by which the robot is mounted on the at least one displaceable running table, the base table, the at least one displaceable running table and the driver means being disposed in a pit defined in a floor on which the robot apparatus is disposed.
A yet still further object of the present invention is to provide a robot apparatus, wherein the running mechanism further includes a guide rail extending in a prescribed direction on the base table, the running table being displaceable along the guide rail.
A yet still further object of the present invention is to provide a robot apparatus, further including a shield member closing an upper open end of the pit and lying substantially flush with the floor.
A yet further object of the present invention is to provide a robot apparatus, wherein the driver means includes a rotative drive source mounted on a side of the base table and having a drive shaft, a pinion coupled to the drive shaft, and a rack fixed to the base table and meshing with the pinion.
A yet further object of the present invention is to provide a robot apparatus, wherein the rotative drive source includes a fluid pressure motor operable by fluid under pressure.
Yet another object of the present invention is to provide a robot apparatus, wherein the running mechanism further includes leveler bolts by which the base table is positioned substantially horizontally.
Still yet another object of the present invention is to provide a robot apparatus, wherein the running mechanism further includes a pair of support plates vertically mounted on the at least one displaceable running table, the attachment member being coupled to the at least one displaceable running table by the support plates.
The above and other objects, features and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which a preferred embodiment of the present invention is shown by way of illustrative example.